Audible fire alarm



A F. WILLAT Feb. 25, 1969 AUDIBLE F IRE ALARM Filed Oct. 31, 1966 n n n I I n m 1 IN VE/VTOH ARNOLD E WILL/1T ATTORNEY United States 6 Claims ABSTRACT OF THE DISCLOSURE An audible fire alarm having explosive caps or powder arranged in the body thereof adapted to be fulminated by heat to emit an audible warning.

This invention relates to audible fire alarms and more particularly relates to fire alarms having an explosive body of powder or of caps enclosed therein, which may be fulminated with a loud warning sound by adjacent heat.

An object of the invention is to provide an audible device for giving a warning responsive to heat of an adjacent existing fire.

A further object is to provide a small, reliable and economical fire alarm which may be conveniently mounted at inconspicuous places in areas where fire may be a hazard.

Another object is to provide a simple, small audible fire alarm which is eflicient, safe, simple and economical.

A preferred form in which the invention may be embodied is described herein and illustrated in the accompanying drawing in which:

FIG. 1 is a planar front elevational view of metallic blank from which the device of the invention may be formed;

FIG. 2 is a perspective rear view of the blank of FIG. 1 with rectangular area formed into an axially elongated roll;

FIG. 3 is a transverse section longitudinally on line 3-3 of FIG. 2;

FIG. 4 is a perspective front view of blank of FIG. 1 with the roll portion (as shown in FIG. 2) flattened to an axially elongated tapered roll;

FIG. 5 is a transverse section longitudinally On line 5-5 of FIG. 4;

FIG. 6 is rear elevational view of the invention at a formative stage illustrating indented creasing of end wings of the rolled portion;

FIG. 7 is a transverse section longitudinally on line 7-7 of FIG. 6;

FIG. 8 is an elevational front view of the completed device of the invention;

FIG. 9 is a longitudinal transverse section on line 9-9 of FIG. 8 the layers in the overfold 29 being necessarily exaggerated to show thickness of the plurality of layers in the rolled metal body;

FIG. 10 is an elevational front perspective view of the casing of the invention after caps therein have been exploded;

FIG. 11 is an enlarged perspective view of roll of caps shown in FIGS. 5, 8 and 9;

FIG. 12 is a perspective view of a strip of caps shown as a roll in FIG. 11;

FIG. 13 is an enlarged front elevational view of a modified form of the invention;

FIG. 14 is a longitudinal vertical sectional view on line 14-14 of FIG. 13;

FIG. 15 is a fragmentary vertical front view of the modified form shown in FIG. 13.

Referring to the drawing in which like reference characters indicate corresponding parts in the several views,

atent O 3,429,293 Patented Feb. 25, 1969 ice the reference character 15 indicates generally the completed device of the invention, which because of the arrangement of its parts, may be more particuarly described by the parts thereof in the order they are formed or put together in the manufacture of the complete device.

Referring firstly to FIGS. 1 to 12, are examples of the invention comprising an integral sheet body 16 which preferably is a planar stamped blank of tough, moistureimpervious resistently-flexible and bendable, non-inflammable sheet metal which may be formed as a planar stamped sheet or blank such as thin sheet aluminum having a rectangular body portion 17 and an integral coplanar tongue 18 extending from one side thereof, the tongue of which may have an eyelet 19 at a free terminal end portion, so that the device may be hung on any suitable support or hook, or nailed at a permanent point if desired. Pliable aluminum sheet of gauge .008 inch is preferred.

To form a casing, the rectangular portion 17 of the blank is rolled upon itself as in FIG. 2 to provide a tubular axially elongated casing roll 20 utilizing within the roll substantially all of the rectangular portions 17, with the planar tongue 18 extending laterally from the longitudinal center of the roll 20, as in FIG. 2. The casing roll 20 is preferably deformed in any suitable manner to provide a partially flattened axially elongated tube 21 which is substantially oval in transverse section and open at its opposite ends, as shown in FIGS. 4 and 5. The opening through this tube 21 is slightly tapered as at 22 for purposes to be described. A charge of an audible explosive powder is inserted into the tube 21 through the larger open end of this oval tube 21, said explosive charge being here exemplified as a flattened roll of explosive caps 23, which is formed as a spiral roll (see FIG. 11), from a paper strip 24 of fulminate caps 25 which are relatively spaced along the strip 24, a series of these spaced caps in a roll being readily provided by the well-known strips of caps of the type generally sold in toy stores to children for cap pistols, and, therefore, manifestly not an explosive force which is dangerous. Approximately ten caps 25 are included in the wad of the spiral roll 23. Because of the taper 22 in the oval roll 21, the flattened wad of rolled caps may be firmly positioned centrally intermediate the ends in the tapered tubular roll 21 by insertion from the larger open end of the roll to a more restricted central portion, and thereby frictionally positioned and held within the tube.

After the roll of caps is inserted into the tapered roll 21 the whole oval tubular roll 20 is preferably partially further flattened as at 26, and the opposite end portions of the flattened oval roll are creased transversely across in spaced relation from each of the opposite end portions of the roll as at 27, which definitely and securely forms a tightly closed and intimately pressure-sealed powder chamber or cap-compartment 28 which closely encloses the roll of caps 23 centrally within the metal roll. The creases 27 do not provide the final closure of the capcompartment of the tubular body, but serve to deform and bring into facial contact the walls of the tube at opposite end portions of the metal cap-compartment 28. Outwardly beyond the creases 27 are small laterally deformed wing tips 29 which are the opposite end portions of the metal roll, and which are intimately over-folded by pressure contact so as to be angular to the general plane of the flattened casing 26 at substantially 45 degrees.

In the next operation shown best in FIG. 9 the opposite wing tips 29 are tightly crimped, as by a suitable clamp, by longitudinal end-to-end squeezing pressure against the ends of said Wing tips 29 whereby they are deformed and flattened tightly as intimate overfolds against the opposite ends of the powder compartment 28, being thus firstly bent laterally or retroverted in one direction from the general plane of the casing at the crease 27, and then having the wing tips 29 retroverted oppositely, or downwardly as shown in the drawing in FIGS. 8 and 9. This also seals the casing 26 and cap-compartment 28 as a compression compartment, for the explosive charges, and also seals said compartment against entry of moisture.

It will be noted that there is no metal-fluxing sealed connection of the rolled and folded sheet metal tube. This is significant in connection with the tough, flexible characteristic of the container body material, which as stated, is moisture impervious, relatively flexible, and noninflammable sheet metal.

From the foregoing description of the detailed manner of making, a very brief statement of the completed structure may be made, firstly in respect of the disclosure of FIGS. 1 to 12, in which form the invention comprises an elongated casing 20 of rolled sheet metal having centrally thereof a flattened compartment 28 for enclosing an explosive charge exemplified as a roll 23 consisting of a plurality of fulminating caps 25 which are preferably spaced and embedded in spirally wound elongated paper strip 24. The closure casing comprises an elongated container body of rolled sheet metal material which has the previously described characteristics, said rolled container casing having an integral laterally extended tongue 18, which may be inserted into a crevice to support the device, or may be provided with any suitable means such as eyelet 19 by which the device may be hung upon a nail or other support. The rolled casing body may be flattened to provide at its central portion a powder chamber or cap'compartment 28 for an explosive charge which may be the illustrated fulminating caps 25. The powder chamber has its opposite ends releasably closed and pressure sealed by a transverse indented crease 27 and a compressed retroverted superficially intimately contacting overfold 29 of the layers of the rolled tubular metal casing at the opposite ends of compartment 28 beyond the creases 27, said tight intimate overfold making the compartment 28 into a releasably tight compression chamber for the explosive charge of caps. This intimate pressure-engaged overfold 29 being formed as previously described, is moisture impervious, but may be supplemented if desired by treating the sealed casing to a coat of moisture impervious paint or vinyl plastic, applied as a liquid and hardening in situ.

In the modification of structure exemplified in FIGS. 13, 14 and 15 alternate structures may be provided in the sheet metal body 16, in which the tongue 18 may have a retroverted hook portion 19a at its free terminal end whereby the device may readily be mounted by hooking over any suitable support, such as on the branch of a Christmas tree. In this modification the metal roll 20 may be formed as previously described, though in this modification the tapering of the roll as at 22 may be eliminated, and one of the creases 27 may be made initially to close one end of a powder chamber 28a, and a charge of heatexplosive powder 23a may be poured into the opposite open end of the tube 21 whereup the said open end of the tube may be closed by a similar crease 27, whereupon the end wings 29 may be overfolded by suitable endpressure, as previously described, which thereby provides the sealed powder chamber 28a.

In this modification the explosive powder charge 23a may consist of a suitable quantity of explosive powder ignitable responsive to a closely adjacent heat of flameinducing high temperature, and especially by direct contact with flame. Ordinary commercial black powder is satisfactory for the purpose, and has the advantage in manufacture that normally it does not fulminate as result of concussion.

To facilitate the explosion of the powder in this modification, it is preferred to provide a fuse or wick 30 which is exposed at all times to the heat of any closely adjacent flame, for which purpose an opening or vent 31 may be provided through one or both of the sidewalls of the powder compartment 23a to expose the enclosed powder to prompt and intimate contact with an adjacent flame. This powder fuse may extend through the opening 31 so as to be even or fiush with the outside surface of the tubular body, as at 26a.

To protect this exposed fuse portion of the powder from any abrasion 'or wear, a transversely enclosing wrapper or band 32 may be provided around the flattened powder compartment and the overfolded ends thereof 29. Preferably this band is paper and is readily inflammable in the area overlying the exposed powder fuse, but may be treated to be non-inflammable at its other portions.

In operation the completely formed devices may be placed at any location where fire is most likely to occur. The smallness and economy of the device makes it practicable to place a substantially larger number of them at unseen positions in corners, cracks, above molding, in closets, on Christmas trees or other inflammable situations. When a fire occurs and the temperature in the immediate vicinity of the fire alarm devices rises sufficiently, an audible warning is given by the explosive charge which will explode with a loud noise. And where there is a plurality of spaced devices they will continue to explode successively as the fire advances and reaches them. But in exploding, the flexible, pliable non-inflammable tough metal of the casing does not dismember and shatter but will unroll at the rolled casing portion 20, and will spread laterally at the overlapped pressure-engaged crease 27 and side wings 29, as shown in FIG. 10.

If desired, the paper cover 24 of the roll of caps or the paper band 31 may be treated at desired portions with any well-known non-inflammable solution such as alum, whereby creeping incineration of the paper may be avoided after the device is exploded.

It is to be understood that the reference to an explosive powder and caps is merely the specific examples and includes solid explosive material and other suitable explosive material.

While the exemplifications herein are described with relation to a flexible metal body folded upon itself into a roll, other forms of folding of the sheet metal body may be adopted, while still preserving the essential element of providing an explosive chamber and an explosive material therein subject to fulmination by external heat, with a flexible metal casing that opens up without shattering responsive to such explosion.

Having described the invention, I claim:

1. An audible fire alarm device having a casing comprising an axially elongated rolled body of tough moisture-impervious, resistently flexible non-inflammable sheet metal rolled upon itself as a tube having longitudinal-1y thereof an elongated closed central compartment, a body of thermally explosive material within said central compartment, the said rolled body having the opposite ends of said central powder compartment tightly and releasably crimped in a transverse pressure seal of the rolled body, said crimped pressure seal being retroverted upon itself in intimate pressure contact, whereby, upon explosion of said powder, the rolled resistently-flexible sheet body and said crimped ends of the rolled body material may unfold without shatter of the sheet metal body.

2. In an audible fire alarm device as provided in claim 1, the said central compartment having an opening through the wall of its rolled body and thereby exposing the explosive material therein to adjacent heat.

3. In an audible fire alarm as set forth in claim 1, and in which said rolled metal casing has an integral tongue having a free end portion extending laterally to the axis of the rolled portion.

4. An audible fire alarm device of the character described, as set forth in claim 1, said rolled casing and central compartment with explosive material therein, having a coating of moisture-impervious material which is normally liquid at time of application and dries and hardens in situ.

5. In an audible fire alarm device as provided in claim 1, and in which the crimping seal of the casing body at the opposite ends of said central explosive material compartment comprises a retroversion of the rolled sheet metal of the tubular casing at its opposite ends in one transverse direction at the opposite ends of said compartment and in the relatively opposite transverse direction at the opposite terminal ends of the casing beyond said :first mentioned retroversion, the seal at the said opposite ends of the casing being [responsive only to the intimate pressure contact of the sheet metal of said casing, whereby upon explosion of said explosive material, said rolled casing may open the roll and the end seals thereof as an integral non-shattered metal sheet.

6. In an audible fire alarm device as provided in claim 1, the said body of explosive material comprising a strip of relatively spaced explosive powder caps enclosed in a paper strip which is spirally Wound upon itself to provide said lbody of explosive material in the casing.

References Cited UNITED STATES PATENTS 138,467 5/1873 Barnes 1l6105 788,225 4/1905 Sweet 116-105 1,746,426 2/ 1930 Hotchkiss 116105 1,840,894 1/1932 Gilbert et a1 116-105 3,087,456 4/1963 Wood 116105 3,299,850 1/1967 Cartier 116-105 5 LOUIS I. CAPOSI, Primary Examiner. 

